How does renewable energy help our future?

Anything that can be used to make heat or electricity without unsustainable fuels and which does not make a net contribution of carbon dioxide to the atmosphere. This includes wind power, waves and the tides, solar energy, geothermal energy and biomass. Nuclear power, although it is low-carbon, cannot be counted as a renewable source of energy because its fuel, uranium, is finite.
How does all of that help our future? Thank you.